|Episode 5 - Incinerator|
Riko is using leaves called amagiri to figure out which direction is north, and navigating her way to the Seeker camp. Suddenly Regu hears someone's cry for help, and they find a monster feeding on a cave raider... But Riko is suspicious, because she knows about this creature, a corpse-weeper that mimics the cries of its dead victims to lure in more victims.
Too late... it turns out there's a ton of these bird creatures, and one of them grabs Riko and starts flying towards its nest to feed her to its babies... Regu tries to save Riko with his extending arm, but the birds keep blocking his attacks. Riko gets sick and passes out immediately from ascending back up towards the surface. Regu suddenly instinctively remembers that he has a hand laser beam and uses it to destroy the whole nest of creatures in a single shot and goes to catch Riko.
Regu looks after Riko until she recovers and wakes up, and he's embarrassed because he had to strip her down half-naked to check for injuries. Riko isn't embarrassed at all, and she talks about how great Regu's incinerator weapon is. Then Regu passes out because of how much energy was drained from using that weapon, and he has a nightmare about Riko being eaten by a corpse-weeper and hearing her voice calling out for help. That's really creepy...
Later, Regu wakes up, and Riko realizes she lost her notebook, but on the bright side she says it'll become a legendary artifact when it's found some day. Regu doesn't want that notebook to be found, since she probably wrote about his "realistic male features" in that book.
Riko cooks a meal from the meat of the corpse-weepers that Regu destroyed. He's kind of disturbed by the fact that they're eating the corpses of other humans, but Riko says it's no big deal.
A montage of them going further down through the 2nd layer, with very few/minor setbacks... and then they arrive at the lowest part of the 2nd layer, the Inverted Forest. Somehow everything here is upside down, including the waterfalls. They get attacked by a bunch of demon monkeys, and Regu can't use his extending arm to take them across a shortcut due to the extreme wind, but can use it to cling onto nearby branches and swing off of them.
After they escape the demon monkeys, it shows some unknown girl spying on them through a telescope, and asking her master if they should set up the gondola for them. I guess this is the "Seeker Camp" that they're headed towards. Regu points out that the wind has calmed down, and there's mostly only peaceful creatures around the area now. Riko explains that they've passed through the central part of the abyss, where the hostile environment is at its worst... I assume by central she means like the horizontal center, and now they're back near the outer perimeter of the hole.
They arrive at the Seeker Camp, but the gondola isn't down yet. Regu wonders if they're too suspicious, being a Red Whistle and a robot. The episode ends just as someone grabs Regu's arms. A narrator introduces her as the White Whistle Ozen, who seems hostile towards these two.